Headlight lens



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L.. BELL HEADLIGHT LENS 'Filed Feb. 15, i920y 2 sheets-sheet 1 may 25, 5525.

L. BELL HEADLIGHT LENS Filed Feb. l5, 1Q2O 2 Sheets-Sheet 2 lfifi 'rentree may entera ,unuTen sTaTes tours enna, or weer NEWTON; MASSACHUSETTS, Anstalten To 'EDWARD TRUSTEE, or NEWTON, MASSACHUSETTS.

^ meeste eeTenT ermee n'. comme,

EEAIDLIGHT LENS.

Application tiled February 13, i920.` Serial No. 358,535.

To all whom it may concern: t

Be it lr'rown that l, Louis BELL, a citizen of the United States, residing'at West Neivton, county of Middlesex, iC'ommonWealth 5 of Massachusetts, have invented certain new and useful improvements in Headlightv Lenses, of which the following is a specification. v y I lin headlight lenses `for road illumina- -ftion-or vehicles, designed to 'redistribute .the beam received from the head-lamp reflector, the peripheral portion of the refracting screen is 'in one Way or another clamped .into the headlam front-usuallywith a clamping vrim holding it in place.'` The clam ing rims'in various headlamps vare of varying widthand construction and with a refractive'. screen of the necessary diameter may. overlap its rim to greater or less extent. There is therefore a marginal portion immediately within the'A rims which either must leave a passage lof .unredistributed light or-be transformed .ingone Way 'or another into an optically 'active surface.

ln my previous Patent, No. 1,277,364, l have dealt with this matter to some extent and with considerable degree of success.

The diculty lies in being able to control rlhis is duesuciently the marginal rays.

to the Ifact that the commercial parabolic reector has a considerable degree of marginal error so that near vthe edge of the. beam there is a considerable quantity of errant rays which are apt to be extremely annoying -in producings'o-called glare.

To overcome this and at the' same time avoid certaindiiliculties which I will here inafter explain, l have devised my present invention. By it 'l have succeeded in sup' pressing these errant rays and done 'so withinvolved in use of the lens with certain types of lens rims.

As illustrative 'of myinvention ll have shown a commercial lens which Well illustrates the principles or" my invention and in itself constitutes a successful embodiment. Throughout the specification and drawin s likereference numerals are cor! `respon ingly employed, 'and in the drawings: l

Vig. l is a iront elevation of a lens in accordance with my 'inventionL- Fig. lll horizontal central' section.

out encountering the mechanical di'lci'ilties Fig. lll' a rear elevation.

Fig. IV a side view, and Fig. V a fragmentary detail illustrating the rim mounting of vsuch a lens.

' lReferring to thedrawings, I have shown thelens `as comprising a central area lfhaving on its 'rear face horizontal prisms and on its front face aeylindric distributing portion 2 best-'shown in Figs. lll and IV. About. thiscentral portion on each Side is, van annul-us inte which thehorizontal prisms and lateral deecting members 'do not exy tend. This ortion is the marginal clamp in area be ore referred to.

vn the rearface-asshown in Fig.' Hl

this portion is heavily stippled as indicated at 3 so as to give a mechanically roughened and opticallydi'using surface. This surface corresponds with the rear annulus of my prior patent above referred to. ln addition to' its optical function of di'using .and suppressing errant rays, it has. the

mechanical function -best illustrated in Figj V. -lnthis mechanical function the roughening at 3 tends to hold .the lens It must be borne in mind, however', that inasmuch as many of the fronts or rimsof headlights are put in place by rotating 'movement that the same Stippling applied in the .treatment of the rear face of the lens for frictional purposes can' not be a 'plied tothe `ron't'iace Without the like i- -hood 'ofthe rim destroying the mechanical grip of the rear face 3 on the felt'padl 4 andy rotating the. lens.

'inthe headlight lenses lia-ving a central 'portion provided with refracting elements,

s ucli central potion is thicker than is necessary 01 desirable in the marginal portion by which the lens is clamped into place. 'To

strengthen the annular rim and vfacilitate its' ,manufactura this rim is usually somewhat thicker toward the center than at the extreme periphery. The eectof this thickening is to constitute' an annular prism which tends tive surfaces adapted to produce dispersion,V

to concentrate the light passing through it and hence to produce a cone of undepressed l and unmodified illumination ahead of the lamp, It is therefore desirable in producin'g an optically active surface on this ann-ulus so to constitute it as to produce sharp ra.

of the type often `known among optical manufacturers as vreecing and applied' to opaque surfaces to diminish reflection,

The face 7 is 4formed with a slight inclination or taper towards the edge to take up any inequality in the edge of the headlight? rim. The headlight rimtherefore lcomes up f Aagainst it with a firm .pressure but on ac count of the circumferential disposition of the diffusing faces the headlight rims may be freely' turned without destroying the fric? .tional grip of the stippled rear face on the felt'pad 4.' The treated annulus 7 therefore permits an important optical supplement of the stippling 3 of the rear face andv like the treatmentV of that face has both an optical and a mechanical function, especially in its combination with the rear face and the ele ments of thelamp rim.

In this'manne'r I am able to form head light lenses with anample mar `nal annulus optically and mechanically su cient to take care of the widest rangeof lamp rims and without the slightest danger of marginal glare. 'Furthermore, these: lenses may be put in, place and the front rim 6 locked by any degree of rotative movement necessary even though several turns might be required under .pressure to effect the locking of'th'e rim. The general optical system 'of such a' lens may be of various types and designs.

of the marginal annulus and in the combina- Various modifications may also be made in the details of the form and extent tion between the front treatment and the roughened rear surface. All such modifications may be made in accordance with my invention and without departing from its claims.

incassa spira if within the ylimits f the appended' what I therefore @aan 'una' desire afge- ,cure by Letters Patent is:

l'ing said elements, the rear: face-'of said mar-y gin being roughened for non-slipping contact with the outwardly disposed bearing of said headlight and thefront face of said annulus having circumferentialdiusing ellements entirelv about its margin and extendposedbearing of the clamping front. f

axis and arranged centrallythereof, and an i annular clamping margin snrrounding said elements, the rear face of said margin being` roughened to prevent rotation, the front face of said margin having concentric circumferential groovings disposed in centering relation to said lens.

3. In combination with a headlight having a fora'ardly Vdisposed lens 'clamping shoulder and a rearwardly bearing 4lens clamping front, a lensr having refracting elements of predetermined function with referencev to a vertical axis centrallyv thereof, and'an annular clamping margin-surroundu ing said elements, the rear face of said annularmarginv having a friction surface adapted to have a non-slip relation to the forwardly disposed shoulder of the' lamp, and the front facecf said annulus having annular extending circular ridges. formed l thereon and'disposed in nonreslsting lrelation to rotative movement of the lens clamp- 2. A headlight lens off the class describedy 'ing withinthe grasp of the-inwardly. disi i In testimony whereof I alixpvmylsignature I j in presence of two witnesses: Y LOUIS' BELL. ,Witnesses:

ESTHER A. PRENTIss. 4

4 MARION F. Wmss. 

